As described in U.S. Pat. No. 7,429,309 B2 to Propst, Jr. et al., which is hereby incorporated by reference in its entirety, modern developments in the art of “papermaking” resulted in the widely accepted Fourdrinier process (See generally Kirk-Othmer Encyclopedia of Chemical Technology, 3rd ed., Vol. 9, pp. 846-7, John Wiley & Sons, New York 1980, herein incorporated by reference in its entirety), in which a “furnish” (a “furnish” is predominantly water, e.g., 99.5% by weight and 0.5% “stock”, i.e., virgin, recycled or mixed virgin and recycled pulp of wood fibers, fillers, sizing and/or dyes) is deposited from a headbox on a “wire” (a fast-moving foraminous conveyor belt or screen) which serves as a table to form paper. As the furnish moves along, gravity and suction boxes under the wire draw the water out. The volume and density of the material and the speed at which it flows onto the wire determine the paper's final weight. Typically, after the paper leaves this “wet end” of the papermaking machine, it still contains a predominant amount of water. Therefore, the paper enters a press section, generally comprising a series of heavy rotating cylinders, which press the water from the paper, further compacting it and reducing its water content, typically to 70% by weight. Thereafter, the paper enters a drying section. Typically, the drying section is the longest part of the paper machine. For example, hot air or steam heated cylinders may contact both sides of the paper, evaporating the water to a relatively low level, e.g., no greater than 10%, typically 2-8% and preferably 5% by weight of the paper. Following the drying section, the paper optionally passes through a sizing liquid to make it less porous and to help printing inks remain on the surface instead of penetrating the paper. The paper can go through additional dryers that evaporate any liquid in the sizing and coating. Calenders or polished steel rolls make the paper even smoother and more compact. While most calenders add gloss, some calenders are used to create a dull or matte finish. The paper can be wound onto a “parent” reel and taken off the paper making machine. The paper on the parent reel can be further processed, such as on a slitter/winder, into rolls of smaller size or fed into sheeters, such as folio or cut-size sheeters, for printing end uses or even office application. The paper can then be coated.
Commercial sub-roofing can include a liner/medium/paper laminated to a layer of expanded polystyrene (EPS). The liner/medium/paper can include glass fibers, typically, in an amount of from 10-25% by weight of the total weight of the liner/medium/paper. In some cases, the glass fibers can provide fire retardant properties. The fire resistant value can be approximately Class A surface flame spread. The final laminated sub-roofing sheet can vary in thicknesses from 1 to 4 inches. The sheet typically has dimensions of 4 feet by 8 feet, corresponding to a standard dimension used in the construction industry. Other sizes may be available for edge finishing of a roof or for custom dimensions of a roof. If the EPS is not laminated electric, air-driven, or manual hammer would be more likely to damage the EPS. With a lamination no damage is incurred to the surface of the EPS when the roofing nail or rivet is driven into the surface.
The color of the liner/medium/paper is typically a medium gray. The liner/medium/paper construction can be resistant to warping when exposed to the elements. A standard test of the current laminated liner/medium/paper EPS product is placing the standard 4′×8′ by variable thickness on blocks and flooded with water and allowed to dry in the hot sun or the cold windy weather and not have warping.
Adding glass fibers to such liner/medium/paper is disadvantageous, because special mills are needed to incorporate the glass fibers and paper fiber to create the current laminating product for the EPS sub-roofing market. It would be desirable to enable any and all paper mills to supply a non-glass fibers blend for sourcing to the sub-roofing market. It would be desirable to develop a liner/medium/paper that mimics the current functions and characteristics of liner/medium/paper that is currently laminated to EPS for commercial sub-roofing. The liner/medium/paper should resist warping of the EPS under severe weather conditions; maintain the gray color (as tested by a trained human eye or by various types of computerized color matching systems) of the existing product; not be slippery during handling and packing; not cause blocking or sticking when the final product is stacked; achieve the correct angle of slide; consistently maintaining the correct resistance to the weather conditions test performances; and have suitable flame resistance and flame spreading properties.
It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings.